Welcome to the CH forums.
Goto Device Manager>View and click on Show Hidden Devices. Search for your camera and external hdd and uninstall them. (the hdd should be listed under Disk Drives, not sure where the camera will appear). Then replug your hdd and reboot, if necessary re-install a driver.
If Show Hidden Devices is not an option in Device Manager>View then Right click My Computer and click Properties. From the Advanced tab, click Environment Variables.
Under System Variables, click the New button. Type devmgr_show_nonpresent_devices for the Variable Name.
Under Variable Value, type "1″ and click OK. Click OK twice more to apply the changes and exit the System Properties dialog box.
Open Device Manager again and from the View menu, click Show Hidden Devices.
Good luck - please post back with your result, good or bad.